"Everything you never wanted to know about the mites that eat, crawl, and have sex on your face". How can you say, "No", to that headline?
Ed Yong has a great post up today at Not Exactly Rocket Science about Demodex folliculorum and Demodex brevis, two species of mites which spend their entire lives on human skin. Humans aren't born with these mites. But by the time you are 40 years old, it's almost guaranteed that you are playing host to a few of them.
The bad news: They are having sex on your face.
Their favourite hook-up spots are the rims of your hair follicles. After sex, the female buries into the follicle (if it's D.folliculorum), or into a nearby sebaceous gland (if it's D.brevis). Half a day later, she lays her eggs. Two and a half days later, they hatch. The young mites take six days to reach adulthood, and they live for around five more. Their entire lives play out over the course of two weeks.
The good news: They don't poop—in fact, they don't even have an anus.
The bad news again: All that waste just builds up in their bodies. Demodex are, by nature, chronically constipated. Only after they die, and their bodies disintegrate, do they finally get to let it all go. All over your face.